737 Max

snipped-for-privacy@optonline.net wrote in news:8f2359e8-478d-4404-8331- snipped-for-privacy@googlegroups.com:

They work as a group, dumbshit.

You must be a street sweeper or perform toilet bowl maintenance for a living.

Reply to
DecadentLinuxUserNumeroUno
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Give us a cite for that.

It only took 3 days and 20 posts to drive that into your head.

So says you. The NTSB that actually investigates crashes and knows how they fly safely doesn't agree:

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aspx?Rec=A-96-094

Safety Recommendation A-96-094

Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Require that all t ransport-category aircraft present pilots with angle-of-attack info in a vi sual format, and that all air carriers train their pilots to use the info t o obtain maximum possible airplane climb performance.

FAA too:

InFO 14010 of Transportation DATE 7/25/14

Background: The FAA is promoting the use of AOA-based systems to reduce GA accidents caused by loss-of-control (LOC). The General Aviation Joint Steering Committee (GAJSC ), including its Safety Assessment Team (SAT), is a joint government and aviation industry group, e stablished with the goal of improving GA safety.

It will cost them billions, but I won't be shedding any tears, they will survive and it was their own stupidity. There may be criminal charges too before it's over.

Now what "dang thing" would that be, Mr. aircraft and Boeing expert?

Reply to
trader4

This is what I hate about trying to have a rational discussion in this grou p. So often people simply don't want to understand things, they are happy to spout totally illogical conclusions. I don't for a minute believe that you really think this is a correct conclusion. No one is actually that poo r of a thinker.

You mean he remembered his training while the others did not. As has been mentioned many times, the correct handling of this situation doesn't even r equire knowledge of the MCAS system, the problem is a runaway trim which is dealt with by shutting off the auto trim.

42

You don't need to know anything about MCAS to recognize the problem.

"some industry players"... in other words, talking heads who are also not w aiting for the facts.

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Reply to
gnuarm.deletethisbit

I haven't seen an intelligent reply to this post. Are you acknowledging that your statement is wrong and you lost the bet?

So will you be paying on the original case of Stella or the bottle of Glenfiddich?

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Reply to
gnuarm.deletethisbit

Out of curiousity, why are there two trim stabilizer disconnect switches? Do they both need to be flipped, or is either one enough? Like are the wired in parallel or series or something more complicated.

piglet

Reply to
piglet

piglet wrote in news:q81nu2$393$ snipped-for-privacy@dont-email.me:

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perhaps separate wing edge trimmers. The elevator, IIRC (and I do not always) is a solid, unitary control surface.

Reply to
DecadentLinuxUserNumeroUno

Good question. None of the articles I found talked about the reason for two switches or how they were wired.

Reply to
Steve Wilson

We know know the Ethiopian pilots did flip the switches. But the serious problem is, that merely removes power to the jackscrew, leaving it in the likely fully extended position. The pilots then have to extend the handles and manually turn the trim wheels, many many turns, as fast as they can, not only to get back to normal, but bring the elevator far the other way, in an attempt to come out of the steep dive. Also, the wheels are not easy to turn, both pilots have to work together, using the 180-deg handle offsets.

It's likely they simply didn't have enough time. Maybe that's why Juan Browne says they only have 45 seconds to discover the problem, hit the switches, and then after that work to get the trim back where it belongs. Given their low altitude, they may have had even less time to discover what to do.

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Reply to
Winfield Hill

Whaaaat? You think you're special? It's rare to see any intelligent response from DL on anything. We all know he was wrong and from his other posts, eg Saddam was fleeing Iraq with a convoy headed for Syria with his WMDs, he just makes up complete nonsense.

I wouldn't hold my breath.

Reply to
trader4

One is on each side, so I would think one cuts off the electric control from the pilot's side trim controls, the other from the co-pilot. There might be two motors driving it too.

Reply to
trader4

Wrong again. The trim is only on the elevator, not the wings.

Reply to
trader4

There is a lot of confusion and ambiguity in the published reports so it's difficult to tell what really happened.

However, as I understand it, the trim switch on the control column overrides MCAS, so all they have to do is return the trim to normal then turn off the switches.

A recent article in Quartz claims

get the plane to climb. They then flipped the switches again to restore power to electrical controls. Just six minutes after taking off, the plane crashed in a field, killing all 157 people on board."

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But maybe what happened is they pulled on the control wheel instead of using the trim switch. The stabilizer is larger than the elevator, so MCAS overpowered thair attempts and continued to turn the jackscrew to full nose down. At 450 feet, you don't have much time to diagnose and correct the problem. In their panic, they became fixated and didn't have time to think of other things to try.

Reply to
Steve Wilson

They might need to both work the crank if it requires a lot of force, I've never seen experts comment on that. I have seen videos where the pilots are in a simulator doing it and it's done easily by one pilot, without even using the crank, just hand turning the one wheel. Which raises an interesting question as to exactly how hard it might be at speed to adjust it if it's all the way at one extreme? The most logical procedure would be to use the trim buttons to move it back close to neutral, then disable it and use manual. It sounds like maybe they were doing that, which would explain why they turned the trim back on. But what happened then? Ran out of time? Or is there something else going on, where the trim buttons won't operate at some point?

That assumes they aren't using the trim buttons on the yoke to correct. The LA pilots did and the plane flew for 10 mins, could have flown until it ran out of fuel, but the pilot handed control to the co-pilot and he only weakly applied counter trim twice, then stopped.

But this is interesting and more troubling, the Ethiopian pilots apparently correctly identified it and the plane still crashed. The big question is exactly why. And with those Ethiopians continuing to sit on the important information, eg CVR, we don't know. At the very least, this shows how this failure is indeed extremely serious and MCAS should never have been implemented relying on one sensor, so forcefully, with continuous action, etc.

Reply to
trader4

The control-column cutoff only works for 10 seconds, before MCAS takes over again. Enough to make them think the problem was solved. By the time they see it's more complicated, the scheme you suggest, use motors for 10 seconds at a time, may be too late.

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Reply to
Winfield Hill

I don't see how they could be fooled into thinking the problem was solved. After correcting the trim with the trim buttons, ten seconds later the trim wheels by their side start spinning again, the indicators show nose down trim being applied by *something* and the plane starts to nose down again. So? Press the trim up button again. It just worked, why wouldn't you just do it again? The LA pilots did exactly that for ~10 mins, then the pilot transferred control to the co-pilot and he stopped doing it.

By the time they see

Reply to
trader4

The Boeing Operations Manual Bulletin TBC-19 states the control yoke trim switch overrides MCAS but it may restart 5 seconds after the trim switch is released:

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Operations Manual Bulletin MLI-15 says the same thing:

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Other links that describe the author's interpretation of these bulletins may contradict or confuse the operation of the electric trim switch. I find articles written by non-pilots to be unreliable.

Reply to
Steve Wilson

.

The latest info on this crash is that the AOA sensor was broken as the resu lt of a bird strike (or some other foreign object). It seems to me this is even more troubling for Boeing because in this instance I don't think the d isagreement light strategy would have helped. I am thinking that the disag reement light strategy helps on the ground prior to takeoff. If the disabl ing of the AOA sensor coincides with the plane going bonkers I am not seein g how the disagreement light helps.

Reply to
blocher

snipped-for-privacy@optonline.net wrote in news:e1a55c52-fb38-40dc-8df5- snipped-for-privacy@googlegroups.com:

Whatever. They turned it back on. Not likely because they thought it was still broken.

Reply to
DecadentLinuxUserNumeroUno

ed.

sult of a bird strike (or some other foreign object). It seems to me this i s even more troubling for Boeing because in this instance I don't think the disagreement light strategy would have helped. I am thinking that the dis agreement light strategy helps on the ground prior to takeoff. If the disa bling of the AOA sensor coincides with the plane going bonkers I am not see ing how the disagreement light helps.

If the crew understands the plane as they should, then the disagree light would let them know that MCAS is likely the cause of the plane trim being driven nose down. But you're right, there is still no guarantee that they would react correctly and the procedure is still the same. The new softwar e is the main fix. It will check for disagreement before the plane leaves th e ground, something that obviously should have been done before, with or withoug a disagree light. The LA flight it was showing extreme angle while the plane was on the ground. And it won't rely on just one sensor to start pushing the nose down, won't push it down as much, will quit if the pilots pull on the controls, etc.

A company in FL repaired the AOA that was put into the LA plane. That still doesn't explain what was wrong with it before, why it apparently still didn't work, what was wrong with the one they had to replace on a plane only two months old. Looks like Ethiopia says they still haven't located the sensor from that crash.

Reply to
trader4

On Wednesday, April 3, 2019 at 7:37:00 PM UTC-4, snipped-for-privacy@optonline.net wrote :

rote:

?

ated.

result of a bird strike (or some other foreign object). It seems to me this is even more troubling for Boeing because in this instance I don't think t he disagreement light strategy would have helped. I am thinking that the d isagreement light strategy helps on the ground prior to takeoff. If the di sabling of the AOA sensor coincides with the plane going bonkers I am not s eeing how the disagreement light helps.

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If the plane is stationary, what would the AoA sensor indicate? I think it would just show whatever position it was last in. Without a fast air stre am to move it, it just sits there. So the AoA would likely not be valid un til at least the plane is moving at some speed.

I'm forgetting my facts from what I've read, but somewhere in one of these incidents was a wash on the ground that should have been done with the AoA covered. Water got into the AoA that froze once the plane ascended. That would not show up on the ground. Was that the Lion Air flight?

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Reply to
gnuarm.deletethisbit

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